Elastic fluid turbine



July 10, 1945. E. E. HARRIS 2,380,237

ELATIC FLUID TURBINE Filed July 29, 1943 ili i 4// Eugene E. Harris,

Patented July 10, 1945 ELASTIC FLUID TURBINE Eugene E. Harris, Latham, N. Y., assigner to General Electric Company, a corporation of New York i Application July 2s, 1943, serial No. 496,569

1 claim. (ci. 25a-e9) tion is of particular interest in connection with turbines which include valve means for controlling the flow of fluid to separate sections of the first stage. In order to obtain maximum eiciency through the entire load range of a turbine it is necessary to extract a comparatively small amount of energy in the first stage or, from another viewpoint, to maintain as high a first stage shell pressure as possible at all loads. In order to accomplish this on machines requiring large volumes of flow the area of the first stage nozzle and bucket vpassages becomes large, requiring first stage nozzle partitions and bucket blades of considerable radial height. In such arrangement the first stage bucket wheel may be subject to excessive bending stresses when elastic fluid is admitted to a short arc only of the first stage,

the turbine.

The object of my invention is to provide anv improved construction and arrangement of elastic fluid turbines of the type above specified whereby high rst stage shell pressure may be maintained during the entire load range without causing excessive bending stresses in the .first stage, especially during partial admission operation. l

This is accomplished in accordance with my invention by the provision of a multi-stage turbine with two first stage bucket wheels arranged in parallel as regards the flow of fluid therethrough and discharging finally into a single bucket wheel of the second stage. In a preferred embodiment channel sectional or partial admission means may be provided for separately conducting the fluid to certain sections of the first stage and for discharging fluid from certain sections or arcs of the first stage wheels into a certain section or arc of the second stage wheel. Thus, under certain operating conditions the fiuid may be admitted over an arc of 50 of eai cf the first stage bucket "wheels and the fluid discharged from these arcs may be conducted to a corresponding arc of about 50 of the single second stage bucket wheel.

For a better understanding of what I believe l 'to be novel anal' my invention, attention is directvention, and Fig. 2 is a section along line 2 2 of Fig. 1.

. The turbine comprises a casing I0 having two halves with a valve chest II for admitting elastic uid thereto and valves I3 in the chest for controlling the flow of fluid to separate sections of the first turbine stag'e. A rotor I6 is disposed within the casing and comprises a shaft I4 with a plurality of bucket wheels I6, Il, I8 and I9 secured thereto. The two bucket wheels I6, I1 in accordance with my invention are arranged in parallel to receive high pressure fiuid supplied to the turbine. To this end the bucket wheels are secured to axially spaced portions of the shaft I I with their inlet sides facing each other. Nozzle sections 20 and 2I are associated with the rst stage bucket wheels I6 and I1 respectively to direct the flow of iiuid thereto. The nozzle. sections 20, 2| form a space between them which is divided by partitions 22 into aplurality of chambers 23 for conducting operating iiuid to separate sections of the wheels I6 and I1. Elastic fluid is conducted to the chambers 23 by means of separate channels 24 connected to the valve chests II.

By using common admission chambers 23 to the two rst stage wheels and allowing the ow to take place in opposite directions there will be a reduction in shaft span for the turbine and a lconsequent improvement in efficiency caused by the reduction of gland leakage and diaphragm packing leakage. Il' two separate independent wheels were to be used and with flow in the same direction, additional length of shaft would be required with comparatively longer shells and about twice the number of control valves. The proposed arrangement thus results in a lower manufacturing cost and better use of materials involved.

The operating fluid discharged from both first stage bucket wheels I6 and I'I is conducted to the single second stage bucket wheel I8. A diaphragm 26 is associated with the second stage wheel I8 for properly ldirecting th'e operating fluid thereto. This diaphragm includes a disk 21 and a plurality of blades 28 attached thereto and forming nozzle passages Vbetween them. In the present example the blades 28 are attached to theright-hand portion of the rim of the disk 21, thus forming .with the bucket wheel Il an annular chamber 29 for receiving the fluid discharged from the yfirst stage wheels IB and I1. The wheel I1 discharges directly into the chamber 29 whereas the wheel I6 discharges into a chamber 30. The annular chamber 29 has a plurality of partitions 3l and alinement with the partitions 22 and the sec-y tional chambers formed between vthe partitions 22 are connected to the sectional chambers formed between the partitions 3i by separate channels 33 formed in the casing.

With this arrangement elastic fluid conducted to one of the nozzle chambers 23 flows therefrom through equal areas of the two rst stage bucket wheels I6 and Il. The fluid supplied to the bucket wheel It is discharged therefrom through a sectional chamber formed between the partitions 32, whence the fluid is conducted through a channel 33 into one of the sectional chambers formed between the partitionsi I. The iluid conducted from a.' chamber 23 to the bucket wheel Il is directly discharged from the latter to one of .the sectional chambers formed between the partitions 3|. n r

During operation a-t full load, elastic iluid is admitted to the first stage bucket wheels I6. I1 over substantially the entire circumference thereof or over a major portion of their admission area so that the total arc of admission for each first stage bucket wheel is more than 180. The fluid discharged from the first sta-8e wheels is conducted to the single b'ucket wheel I8 of the second stage located adjacent the bucket wheel I1. 'I'he fluid discharged from the bucket wheel I6 is conducted to the second stage wheel I3 through the separate channels 33, 3| formed within the casing. During partial admission operation only one of the valves I3 in the chest I I may be opened so that operating fluid is conducted to like arcs of the first stage bucket wheels I6 and I1 and discharged therefrom through the annular chambers 29, 30 to a corresponding arc of the second stage bucket wheel I8.

The iluid from wheel I6 passes .through chamber 30, through passageways 33, into the chamber 29, while fluid from wheel I1 is discharged directly into the chamber 29. As pointed out above, in the present example the annular chamber 29 has a plurality of circumferentially spaced partitions whereby fluid discharged -from any section or sections of the first stage bucket wheels is directed to a. certain section or sections of the second stage bucket wheel I3. In some instances the circumferentially spaced partitions in the annular chambers 20 and 3l may be omitted in which case fluid discharged from any section of the ilrst stage bucket wheels is distributed around an arc of 360 in the chamber 2l for admission over -the entire inlet area of the second stage bucket wheel I3. f

The fluid discharged from the second stage Ibucket wheel I3 is conducted to the third stage bucket wheel I3 through the intermediary of a tatilo'nary diaphragm 3l supported on the cas- A turbine according to my invention may beA used with advantage as a high pressure turbine ahead of a double-now, low pressure turbine of the type described in Patent 2,102,416 to O. Junggren. issued December 14, 1937, and assigned to the same assignee as the present application.

Having described themethod of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

An elastic fluid turbine comprising a casing, 'a shaft supported therein, two rst stage bucket wheels mounted on the shaft, partial arc admission means in the casing between the bucket wheels arranged to deliver operating medium to Iboth wheels in parallel flow relation, valve means for controlling thefilow of operating medium to the respective arcs of the first stage wheels, a second stage wheel mounted on the shaft adjacent one of the rst stage wheels, partial arc admission means arranged to deliver operating medium from both first stage wheels to the second stage wheel, and walls defining passages in the casing arranged to conduct operating medium directly from an arc of each of the ilrst stage wheels to a certain arc of the second stage wheel so that both rst and second stage wheels may be operated with partial arc admission.

EUGENE E. HARRIS. 

